Cutting torches are frequently used to cut metal, including metal cables. Some of the applications in which it may be desired to cut metal include, but are not limited to, concrete members that may include tensioning strands, rebar, or the like.
Many structures are built using concrete, including, for instance, buildings, parking structures, apartments, condominiums, hotels, mixed-use structures, casinos, hospitals, medical buildings, government buildings, research/academic institutions, industrial buildings, malls, bridges, pavement, tanks, reservoirs, silos, foundations, sports courts, and other structures.
Prestressed concrete is structural concrete in which internal stresses are introduced to reduce potential tensile stresses in the concrete resulting from applied loads; prestressing may be accomplished by post-tensioned prestressing. In post-tensioned prestressing, a tension member is tensioned after the concrete has attained a specified strength by use of a post-tensioning tendon. The post-tensioning tendon may include anchors, the tension member, and sheathes or ducts. A tension member is conventionally constructed of a material having sufficient tensile strength that can also be elongated. Tension members are conventionally formed from a strand and a sheath. The strand is conventionally formed as a single or multi-strand metal cable. The strand is conventionally encapsulated within a polymeric sheath extruded thereabout to, for example, prevent or retard corrosion of the metal strand by protecting the metal strand from exposure to corrosive or reactive fluids. Likewise, the sheath may prevent or retard concrete from bonding to the strand and preventing or restricting movement of the sheath during post-tensioning. The sheath may be filled with grease to further limit the exposure of the metal strand and allow for increased mobility. The post-tensioning tendon conventionally includes an anchorage at each end. The tension member is fixedly coupled to a fixed anchorage positioned at one end of the post-tensioning tendon, the so-called “fixed-end”, and stressed at the other anchor, the “stressing-end” of the post-tensioning tendon.
The concrete may be poured into a concrete form. The concrete form may be a form or mold into which concrete is poured or otherwise introduced to give shape to the concrete as it sets or hardens thus forming the concrete member. The post-tensioning tendon may be positioned within the concrete form, the concrete poured, and the concrete member then stressed to form a concrete segment. After the concrete member is stressed, the tension member extends beyond the edge of the concrete segment. In some cases, a pocket former is placed around the strand before the concrete is poured, which results in a pocket in the cured concrete. The end of the strand extends outwardly from the concrete and, if a pocket former was used, the end of the strand extends through and outwardly from the pocket. Conventionally, at least a portion of the strand that extends beyond the edge of the concrete member is cut, such as by a cutting torch. If a pocket former was used, the cutting of the strand may take place in the pocket.
Cutting torches generate sparks during the process of cutting the strand. Sparks generated by cutting torches may cause fires in nearby flammable materials. Such fires may result in damage, danger to personnel, delays, and increased monitoring costs.